Flat-panel type picture display device

Abstract

A picture display device has a vacuum envelope and is provided with a face plate whose inner side supports a luminescent screen, a rear wall situated at a short distance therefrom, and the space in-between accommodating a plurality of electron sources, which cooperate with a plurality of electron transport duct including dielectric walls fro transporting, through vacuum, the produced electrons towards positions at a small distance from the luminescent screen. The display device further includes means for reducing the effects of undesired charge transfer of the duct walls, which are provided to improve the start-up and/or steady state electron transport conditions. Specifically, the outer sides of the duct rear walls are provided with a conductor to which an initiation potential is applied, which is equal to or higher than the potential applied for producing the electron transport field.

We claim: 
     
       1. A picture display device having a vacuum envelope which is provided with a transparent face plate with a luminescent screen for displaying pictures composed of pixels, which display device comprises a plurality of sources for emitting electrons, electron transport ducts cooperating with the sources and having walls of a dielectric material for transporting secondary electrons, initiated by wall interactions with the emitted electrons in a longitudinal direction past openings in the ducts at a short distance from the luminescent screen, and means for accelerating the electrons from said openings and toward the luminescent screen, characterized in that the transport ducts have a width/height ratio which does not differ more than 25% from 2/3. 
     
     
       2. A picture display device having a vacuum envelope which is provided with electron transport ducts cooperating with sources for emitting electrons and means for extracting electrons from the electron ducts, characterized in that the transport ducts have a width/height ratio which does not differ more than 25% from 2/3.